Filter



All@ :21, 1951 c. A. wlNsLow ET AL 2,565,445

FILTER V Filed Sept. 16, 1946 2 Sheets-Sheet l A Tram/5y Aug. 2l, 1951c. A. wlNsLow E1- AL 2,565,445

FILTER Filed Sept. 16, 1946 2 Sheets-Sheet 2 'sa l //V VEN 7'0/25CHARLES A. w/NsLow W/LL/AM G. NOSTEAND BYLAUENCE .MOOE

Patented Aug. 2l, 1951 FILTER Charles A. Winslow, William G. Nostrand,and Laurence L. Moore, Oakland, Calif., assignors to Winslow EngineeringCo., Oakland, Calif., a

partnership Application September 16, 1946, Serial No. 697,222

4 Claims.

This invention relates to filtering apparatus and, more particularly, tofiltering units comprisingI a number of replaceable filtering elementscontained within a housing for filtering fluid fed into the housingunder pressure through one conduit, the filtrate being discharged fromthe housing through a second conduit, and the residue being retained onor in the filtering elements until they are removed and replaced byclean elements.

Filtering units of the type to which the invention relates find wideusage in association with various types of machines, particular internalcombustion engines, for filteringsludge, grit, and other deleteriousmatter from lubricating oil employed in a circulating oil system. Asidefrom certain limitations on the life and effectiveness of the individualfiltering elements. filtering units of this general type employedheretofore have possessed a number of disadvantages that seriouslyimpair their suitability for many types of uses and that have even beenresponsible in numerous instances for extensive damage to ma chines withwhich they are associated. For example, it has been customary to employcheck valves in these filtering units to by-pass unfiltered lubricantaround the filtering elements wh-en they become clogged in order toinsure an uninterrupted iiow of lubricant through the unit. These checkvalves were so placed in the units that large quantities of sludgepresent in the unfiltered lubricant tended to accumulate in and aroundthe valve passages. When the valves opened in vresponse to excessivepressure developed in the unfiltered lubricant chamber of the units, thesurge o1' fluid through the valves frequently carried slugs or globulesof sludge out of the units through the outlet conduits. In cases wherethe outlet conduits supplied lubricant directly to bearings and thelike, sludge passing through the check valves in the mannerVd-escribedwas apt to be fed directly onto the lubricated surfaces, thereby greatlyaccelerating their rate of wear.

Another common deficiency of prior filtering units having a largechamber for receiving lubricant to be filtered was that the lubricanttended to drain through the filtering elements and the outlet conduitsor back out of the outlet conduits, ultimately flowing into thecrankcase or other reservoir in the associated machine during periodswhen the machine was not in operation, thereby temporarily raising thelubricant level in the reservoir. If the machine operator checked thelubricant level in the reservoir before placing the machine back inoperation, he would get one reading on the lubricant gage, whereas, ifhe had check-ed the level immediately after the machine was stopped andbefore lubricant could drain out of the filtering unit in quantity, hewould have gotten a substantially smaller reading on the lubricant gage.The higher reading was not representative of operating conditions, andoperators were frequently deceived thereby into believing an adequatesupply of lubricant was present when such was not actually the case. Asa result of such errors, machines frequently were operated withoutsufficient lubricant, with disastrous results.

Another objectionable feature of prior filtering units of the generaltype to which this invention relates was that the examination andreplacement of filtering elements was difficult without removing theentire unit from its mounting or handling the coated and saturatedfiltering elee ments individually during their removal from the unit.

It is an object of the present invention to provide a filtering unit ofthe general type described having a greatly decreased tendency for slugsor globules of iilterable material to by-pass the filtering elements andpass out of the unit through the outlet conduit.

Another object of the invention is to provide a filtering unit of thegeneral type described from which fluid will not drain by gravity backinto the fluid system with which the unit is employed when the supply offluid to be filtered is cut 01T, as by stopping operation of a machineserved by the unit.

Another object of the invention is to provide a filtering unit of thegeneral type described in which the various filtering elements aremounted for easy removal as a single unit without the necessity forhandlingthe filtering elements individually and without having to removethe entire unit from its mounting.

Another object of the invention is to provide a filtering unit of thegeneral type described that is simple in construction, inexpensive tomanufacture, and eicient in operation.

Still other objects and advantages of the invention will become apparentfrom the following detailed description of a preferred embodimentthereof, selected for illustrative purposes, and from the accompanyingdrawings. The particular embodiment of the invention employed forillustrative purposes is one specially designed for filteringlubricating oil in mobile Diesel engine plants, such as those employedto power large trucks, busses, tractors, and other vehicles, but it isto be understood that the invention is not limited physically to theprecise structural details disclosed and is not limited in its utilityto association with machines such as those named or to the filteringonly of lubricating oil.

Referring now to the accompanying drawings- Fig. 1 is a, verticalsectional view of a filtering unit, the filtering elements containedtherein being illustrated somewhat schematically;

Fig. 2 is a horizontal sectional view of the filtering unit, the planeof the section being indicated by the line 2-2 in Fig. 1;

Fig. 3 is a plan view of the filtering unit;

Fig. 4 is a vertical sectional view of a portion oi' the filtering unit,the plane of the section being indicated by the line 4-4 in Fig. 3; and

Fig. 5 is another vertical sectional view of a portion of the filteringunit, the plane of the section being indicated by the line 5-5 in Fig.3.

The filtering unit shown in the drawings is contained in a housing II,preferably having the form of a circular cylinder, though a wide varietyof cylindrical shapes may be employed as may be dictated by spacelimitations or other considerations. The housing may be mounted inassociation with other equipment or machinery in any convenient manner,as, for example, by means of a bracket I2 adapted to be clamped tightlyaround the housing II by a plurality of fastening elements I3. Oil to befiltered is admitted into the housing Il through an opening defined by ahollow boss I4, preferably located near the top of the housing. Thebottom of the housing is closed by an integrally formed, dished wall I6,in which may be mounted a hollow boss I1 dening an outlet opening forfiltered oil and another hollow boss I8 defining an opening for use inwashing accumulated sludge and grit out of the housing. The latteropening is normally closed by a removable plug I9.

The inner end of the hollow boss I1 extends a short distance into thehousing I I and terminates in an outwardly extending annular flange 2 Ithat serves a purpose described hereinafter. The inu wardly projectinglength of the boss I1 is internally threaded to receive and secure oneend of an outlet conduit 22 that extends axially up through the housingI I into close proximity with the upper end thereof.

The upper end of the housing II is provided with an outwardly extending,annular flange 23; and a cap 24, most conveniently formed as a metalcasting, closes the upper end of the housing and is secured to theflange 23, with a suitable sealing gasket 26 interposed therebetween, bymeans of a number of bolts 21. An integrally formed, cylindrical portion28 of the cap 24 projects a short distance downwardly inside the housingII and engages a plate 29 that cooperates with the cap 24 to define arelatively small upper chamber 30 therebetween. A small vent hole 3| ispreferably provided in the cap 24 leading into the upper chamber 30.

The plate 29 is centrally apertured so that the outlet conduit 22 mayproject upwardly therethrough and a short distance into the upperchamber 30, the outlet conduit being provided with an outwardlyprojecting, annular flange 32 supporting an annular sealing gasket 33,that in turn bears upwardly against the plate 29 for preventing leakagearound the outlet conduit where it passes through the plate 29.

The cylindrical portion 28 of the cap 24 is provided with a number ofcircumferentially spaced apart lugs 34 around its inner periphery, thelugs being drilled and tapped to receive respective screws 36. The plate29 is apertured at appropriate points around its periphery so that thescrews 36 may be passed through the apertures and threaded into the lugs34 for holding the plate tightly against the portion 2B of the cap,Thus, removal of the bolts 21 permits the cap 24 and the plate 29 to belifted from the housing to give access to the interior thereof forinstalling or removing the filtering structure now to be described.

The filtering structure contained within the housing II consists of anassembly that may be installed and removed as a unit. This assemblycomprises a plate 31, that may be of any convenient configurationadapted to drop freely into the housing II. The plate 31 is centrallyapertured for loosely encompassing the outlet conduit 22, the aperturebeing sufficiently small, however, so that this plate may rest upon andbe supported by the flange 2l on the outlet boss I1. A plurality oftubes or pipes 38, four being employed in this`instance, are disposed inuniformly spaced apart relation about and parallel to the central outletconduit 22, and the lower ends of the tubes are rigidly secured to theplate 31, as by welding, so that these ends of the tubes are closed bythis plate. The walls of the tubes 38 are provided with numerous smallapertures or perforations 39 through which filtered oil may flow intothe tubes, and the upper ends of these tubes project with snug slidingts through suitable registering apertures in the plate 29 and extendinto the upper chamber 38 for discharging filtered oil into thischamber. Preferably, the upper ends 0f the tubes 38 terminate somewhatabove the upper end of the outlet conduit 22.

Each of the perforated tubes 38 is surrounded. for the full portion ofits length below the plate 29 by one or more elongated, annular,filtering elements 4l, both end portions of each such eiement being heldsnugly around the tube on which it is mounted and the elements beingslightly compressed longitudinally between the two plates 29 and 31. Asuitable ltering element for this purpose may comprise a core of fibrousfiltering material 42, intermixed with any desired oil purifyingmaterial; a porous, knitted fabric, covering material 43 wrapped aroundthe inside, outside, and ends of the core; a pair of snap springs 44enclosed in the opposite ends of the fabric covering for holding theends of the element in engagement with the hube 38 on which it ismounted; and a helical spring spacer coil 46 inserted inside the fabriccovered core to maintain a desired space between the inner surface ofthe element and the perforated tube 38; the whole being assembled in themanner disclosed in U. S. Pattent No. 2,314,640, issued March 23, 1943.Filtering elements properly fabricated as taught in the above-mentionedpatent are somewhat flexible and normally grow in volume as deleterioussubstances are collected and absorbed within the bodies of the elements.The snap springs 44 may be simple helical springs having their oppositeends hooked together to form constricting rings for holding. the endportions of the elements in more or less sealing engagement with thetubes 38.

The above-described filtering structure may be assembled with a suitablenumber of filtering elements 4I\.before it is inserted into the housingII, and, similarly, it may readily be lifted out of the housing forcleaning the interior thereof and replacing used filtering elements withnew ones. .Under normal operating conditions, oil is pumped underpressure to the filtering unit through a suitable conduit (not shown)and is introduced into the housing through the inlet opening in the boss|4 until the main chamber 41 is filled with oil. As the oil pressurewithin the main chamber 41 rises, the oil is forced through the bodiesof the several filtering elements 4|, leaving deleterious materialformerly suspended in the oil deposited on the outer surfaces and withinthe cores of the filtering elements. On being forced through thefiltering elements 4|, the filtered oil iiows through the perforations39 in the tubes 38; and when these tubes are full, the filtered oilflows upwardly therein and out of their upper ends into the upperchamber v3|). As the oil level in the upper chamber 30 reaches the upperend of the outlet conduit' 22, it fiows down this conduit and out of theoutlet opening in the boss I1, from where it may be conducted by gravitythrough any suitable conduit (not shown) to surfaces to be lubricated orto a filtered oil reservoir.

To provide for maintaining a continuous iiow of oil through thefiltering unit in the event the filtering'elements 4| should become tooclogged with sludge to permit normal flow therethrough, one or morecheck valves should be incorporated in the unit to by-pass unfilteredoil from the main chamber 41 directly into the upper chamber 30. In thepresent case, four such check valves, oi more or less conventionaldesign, are built into the cap 24. 'I'hese valves may be housed withinsuitable cavities 48 defined by hollow bosses 43 formed'integrally withthe cylindrical portion 28 of the cap 24, the valve cavities beingpartially closed by the plate 29. An aperture for each valve is providedin the plate 29 to form a port against which a ball 52 is normallyseated, the ball being urged toward its seat with a predetermined `forceby a helical spring 53. A gap 54 between the inner portion of each boss49 and the plate 29 permits oil passing through the ports 5| to flowfreely into the upperk chamber 30. Thus, when the pressure of unfilteredoil in the main chamber 41 exceeds a value determined by the strength ofthe springs 53, unltered oil is permitted to flow upwardly through thecheck valves and into the upper chamber 30, thereby compensating for anyreduction or interruption in the flow of oil through the filteringelements 4f.

'Ihe particular check valve arrangement disclosed has two principaladvantages. Firstly, the valves are located at the very top of the bodyof unfiltered oil in the main chamber 41 so that sludge and grit are notinclined to settle in and around the valve ports 5|; and secondly, thevalve ports 5| merely comprise holes drilled through the plate 29 sothat there are no protuberances or irregularities tending to catch andhold sludge or grit where it can be washed through these ports. Thesmall distance that the upper end of the outlet conduit 22 projectsabove the bottom of the upper chamber 30 provides some additionalprotection against the possibility of slugs or globules of solidmaterial fiowing into the outlet conduit, a sufiicient oil depth beingmaintained in the upper chamber for such slugs 0r globules to settle andaccumulate therein if they should happen to pass through the checkvalves.

Since both the inlet opening for introducing unfiltered oil into theunit and the outlet for filtered oil leaving the chamber 30 are disposedadjacent the top of the unit, it is obvious that only an insignificantportion of the total oil content of the unit can lflow therefrom bygravity when the supply of unfiltered oil ceases incident to stoppingoperation of machinery with which the unit is associated. Thiseffectively avoids all danger of the type of false oil level readingsdescribed hereinbefore.

Because the unfiltered closely adjacent the check 56 is preferablymounted in the main chamber 41 so that its upper edge abuts the plate 29and its side edges abut the wall of the housing the baille being sopositioned with respect to the inlet for unfiltered oil that theincoming stream is directed downwardly for a substantial distance. Thisminimizes turbulence in the vicinity of the check valve ports 5| whichmight otheron inlet' is disposed valve ports 5|, a baie wise tend tocarry suspended solid material through these 4ports when the checkvalves are open.

From the foregoing description of a preferred embodiment of theinvention and its mode oi' operation, it will be appreciated that a,filtering unit has been provided that is simple and economical tomanufacture, is simple to service while in use, and yet provides maximumprotection against the dangers described hereinbefore. While thisdisclosure has been made by describing a specific embodiment of theinvention in detail, it will also be appreciated that the novel featuresof the invention are capable of taking a variety of specific forms andof being used in performing numerous types of filtering operationswithout departing from the true scope of the invention as defined in theappended claims.

We claim:

1. A liquid filtering unit comprising a cylindrical housing having anopen upper end, an inlet adjacent thereto, a closed lower wall and anoutlet opening therethrough; a conduit secured at its lower end aroundsaid outlet opening and extending vertically upward therefrom a plate insaid housing above said lower wall, said plate having an aperturetherethrough to provide a detachable slip joint around said conduit; aplurality of perforated tubes secured at their lower, closed end to saidplate and extending vertically upwards therefrom; a correspondingplurality of tubular filtering elements surrounding each of said tubeswhereby liquid passing into vsaid housing is filtered into said tubes; asecond plate closing the upper end of said housing, said plate having aplurality of apertures to provide detachable slip joints around saidconduit and said tubes, and a cap, secured to said housing above saidsecond plate and recessed to provide space therebetween, wherebyfiltered liquid passes from said tubes into said space and then outthrough said conduit.

2. The filtering unit claimed in claim 1 in which there is a bypassmeans adjacent said inlet to pass unfiltered liquid from the spacebetween said plates into the space above said second plate when theliquid pressure exceeds a predetermined amount, and in which there is abaille in said housing adjacent said inlet between said inlet and said|by-pass means to deflect liquid so that it will not pass directly fromsaid inlet through saidbypass.

3. A liquid filter comprising a cylindrical casing having an inlet nearits upper, open end and.

an outlet through its bottom wall; a removable hollow cap closing saidupper end, said cap having a lower wall; a central outlet conduit fixedto said casing at its outlet and extending axially upward from saidoutlet into said hollow cap. the connection between the lower wall ofsaid hollow cap and said conduit comprising a detachable slip joint; afilter element support plate within said casing at its lower end andsupported around said outlet conduit by a detachable slip joint; aplurality of perforated tubes permanently fixed to said plate and closedat vtheir ends thereby, and extending vertically upward therefrom intosaid cap higher than said outlet conduit, the connection between each ofsaid tubes and the lower wall of said hollow cap comprising detachableslip joint; and a removable lter element around each said tube, wherebythe illter assembly comprising said plate, tubes, and i'llter elementsmay be removed from said casing as a unit for replacement of the` filterelements.

4. The filtering unit claimed in .claim 3 in which there is a bypassmeans adjacent said inlet to pass unfiltered liquid into said hollow capwhen the liquid pressure'exceeds a predetermined amount and in whichthere is a baille in said housing adjacent said inlet between said inletand said by-pass means to deect liquid so REFERENCES CITED 'Thefollowing references are of record in the ille of this patent:

UNITED STATES PATENTS Number Name Date 655,841 Watson et al Aug. 14,1900 1,203,835 Zahm Nov. 7, 1916 1,734,325 Cannon Nov. 5, 1929 1,992,101Stuart Feb. 19, 1935 2,057,932 Baiser Oct. 20, 1936 2,108,087 ThayerFeb. 15, 1938 2,113,923 Miller- Apr. 12. 1938 2,261,098 Wicks Oct. 28,1941 2,280,033 Aldham Apr. 14, 1942 2,294,262 Wilkinson Aug. 25, 19422,345,848 Winslow et al.r Apr. 4, 1944 2,374,976 Briggs et al May 1,1945 2,390,494 Briggs et al Dec. 11, 1945 A2,406,308 Vokes et al. Aug.20, 1946 Brecque Oct. 21, 1947

